Re: [PATCH 00/22] KEYS: Support TPM-wrapped key and crypto ops

[David Woodhouse]

On Thu, 2018-09-20 at 09:26 +0200, Marcel Holtmann wrote:
> Hi David,
> 
> > > > Yes.  It shouldn't be much code, either.  You still have to check for X.509
> > > > DER since the kernel currently supports that.
> > > 
> > > For reasons of backward compatibility, correct?  The kernel also has
> > > mscode.asn1 which we would need to support as well.  Since we can't break
> > > compatibility then perhaps this doesn't buy us a whole lot in the end.
> > 
> > Don't worry about mscode - that's not an asymmetric key parser.  That's only
> > ever used directly from verify_pefile_signature().
> > 
> > Currently, we have to retain support for DER-encoded X.509.
> > 
> > But there's no reason we can't have a PEM parser that decodes the PEM and
> > selects X.509, PKCS#8 or TPM based on the ascii header in that.  PKCS#8 and
> > TPM don't need to take DER directly.
> 
> since we have to support DER-encoded anyway, can we get the current
> patches merged (with fixes to the commit messages for the openssl
> examples if needed) and then work on PEM support inside the kernel.
> For me these seems to be two independent features. And in the current
> form the patches have been tested and used.
> 
> Or let me ask this differently, are there any objections to merging
> these patches with just DER support?

Let me rephrase that question slightly: Are we happy to have to make
inferences from the ASN.1 structure, and in particular that a bare
OCTET-STRING is a TPMv1 blob? I believe James ended up doing something
somewhat more sensible for the TPMv2 blob so that might end up being
OK...?

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